The potential for irreparable disaster at any of the 104 nuclear reactors in the U.S. far outweighs any alleged benefits from the controversial energy source, according to the panel, which included Gregory Jaczko, former Nuclear Regulatory Commission chair during the Fukushima Daiichi accident in Japan; Peter Bradford, an NRC commissioner during the Three Mile Island accident; Arnie Gundersen, nuclear engineer; and Naoto Kan, former Japanese Prime Minister.

The panelists unanimously "condemned the ongoing delay of the Nuclear Regulatory Commission to require stricter safety measures at the nation's 104 reactors following Fukushima Daiichi," Cape Cod Times reports.

It may only be a matter of time before the next incident like Three Mile Island, Chernobyl or Fukushima, Gundersen warned.

The focus of the public discussion, which convened at the Massachusetts State House in Boston, was Plymouth, Massachusetts' 41-year-old Pilgrim Nuclear Power Station. Pilgrim was granted another 20-year operating license in 2012.

"Is Pilgrim any different from Fukushima Daiichi? The reactor is identical to Daiichi's units 2 and 3," Gundersen said. "In a critical way, it's worse. The Japanese have seven or eight years of spent fuel stored there, we have 35 years of spent fuel sitting in a pool in Pilgrim, and the pool sits on top of a building."

"Accidents will happen," Jaczko said. "That doesn't mean Pilgrim will have an accident tomorrow or in my lifetime, but it's a possibility that can't be ruled out."

Joining the panel last minute, State Sen. Daniel Wolf (D-Harwich), who represents communities on the Cape, said he is concerned about the Pilgrim site in particular after a recent visit there.

"Based on what I saw, just on skin level, the place looked like the 1960s and 1970s technology right down to analog warning lights," Wolf said. "I got off the elevator onto flypaper. When I asked what it was for, they said to take radioactive material off your feet."

Wolf said that recent "warning signs" should be heeded, such as ongoing mechanical glitches that plague Pilgrim. "Aging systems fail. Period," he said.

"After experiencing the [Fukushima] disaster of March 11, I changed my thinking 180 degrees completely," said Kan, who was in office at the time of the meltdown. "We do have accidents … and sometimes hundreds of people die in an accident. But there's no other accident that would affect 50 million people—maybe a war—but there's no other accident so tragic."

"If humanity really worked together, we could generate all of our energy through renewable energy. I firmly believe that," Kan said.

"There is only one way to eliminate accidents," he said, "which is to get rid of all nuclear power plants."